Overheating in the afternoon in the summer after replacing fan clutch, & OEM ford Motorcraft thermostat.

[73IDIBenoit]

I’ve got a 1993 7.3 idi NA with an overheating issue. I’ve replaced the fan clutch, & thermostat with good quality parts. OEM Motorcraft thermostat was installed to prevent this.

Truck ran great, except for when I get on it up a hill. I’m running 50/50 atf to diesel with a tad of wmo. Truck has previously ran on a 75wmo/25gas last summer just fine.

I’m in college rn, & I’m freaking out. The previous owner replaced the water pump, & used too much rtv. I found it in the thermostat, & a giant chunk in the radiator I fished out. I’m nervous it’s the freakin radiator.

I have stock IDI injectors in the truck, & IP is untouched/stock, she smokes a tad when I floor it or if I work it hard.

I’ve thought that my gauge is kinda wonky, but I don’t trust it to risk my motor.

Please help!!!

 

[Jesus Freak]

I run like 90%wmo in NW Florida, so that's not an over heating issue. It really sounds like a radiator. Is it the original radiator? Can you see any deposits of stuff in the filler hole?

 

[73IDIBenoit]

Yeah it’s stock radiator.

 

[Jesus Freak]

Ughh, well, that's 30yrs of potential build up. Consider doing a big drain and flush.

 

[73IDIBenoit]

I rebuilt my oil cooler 6-8 months ago, drained my coolant, & filled with fresh. The old stuff came out nice, & clean. The coolant side of things in the oil cooler was clean, & did not seem to have excessive buildup.

There’s times I’ll get on it in 4th & stay in it up a hill rolling black smoke then it’ll get hot, then when I ease off it’ll cool off. Then sometimes it’ll get to a temp where it won’t go down until I turn the truck off or unless I sit at a light, & rev the engine up to cool the radiator off then it comes down.

The annoying part is that I had bought a radiator to instal in it, then returned it cuz I didn’t think I’d need it.

 

[73IDIBenoit]

If I look into the filler hole I can see little bits, & chunks of stuff in my cooling slots. Then I see the tops of em that look to be partially corroded from the coolant. Before I replaced my fan clutch, & my thermostat I power washed part of my radiator, & it helped a tad.

 

[Jesus Freak]

It really sounds like clogged flues in the radiator.

 

[Joezam]

Sorry to mention something simple, but it sounds like the temp sending unit.

 

[Robert Barreras]

I live in Southern Arizona I have a 2004 Dodge ram 5.9 Replaced the vestronic radiator fan 3 times $$$$ did not work put an external electric fan on the front and reversed the fan so it pulls air in, this is mechanically switched , problem my problem Solved.

 

[Ranchdweller]

I know I’m a little late to the party, but check your transmission. I added a trans cooler and lowered my engine temp.